Starting new campaign. How long should I test it for?

[voltrader]

I'm starting a new campaign for keywords that are more expensive than what I've been used to playing with.

The affiliate cookie lasts for 45 days. Given the likelihood of cookie overwriting, parasites, and the propensity for looking-then-never-buying, how long should I test the campaign to get a good handle on ROI?

Anyone have any rules of thumb to use?

Any advice would be helpful.

[louki]

I'd like to hear some ideas about this as well... I've tested here and there but without being able to figure out a trend. I've started/stopped to see if conversions catch up... increased/decreased bids to see if it changes.

Of course, what may work for one person may not for another and each program/situation is different... but it would be great to see what the regulars here might be thinking.

[suzyvirtual]

If you don't have the cash to hang in for at about 30 days after the cookie period (so in your case 75 days), you probably shouldn't bother starting that campaign just yet.
Obviously, there are feedback signals, I wouldn't recommend hanging in for that long if you are getting no (or virtually no) sales, but if you are making about %65-%70 (or more) ROI in the early days, it is worth riding out to see what happens.
You can always start with lowish bids though, and increase as you start getting some cookie saturation.

[voltrader]

Thanks suzy -- I'll hang around for 30 days or so to test "cookie saturation" and reduce the ROI lumpiness.

That'll also give me enough data to test for keyword conversion.

I was getting triple digit ROI in the first few days, then I had two days of zero sales, then in the early hours of the morning (PST) it picked up a little.